Slide fasteners are opening and closing tools of articles which are used in daily necessities such as clothing, bags, footwear and household goods, as well as articles which are also used in industrial goods such as water storage tank, fishing nets and spacesuits.
FIG. 1 shows a structural example of a slide fastener. The slide fastener 10 is mainly composed of three parts which are a pair of elongated tapes 11, a number of elements 12 that are engaging parts of the fastener attached along one side edge of each tape, and a slider 13 for controlling the opening and closing of the fastener by engaging and separating the elements 12. Furthermore, a top stop 14 and an opener 15 can be provided in order to prevent the slider 13 from falling off, and on the surface of the slider 13, a pull tab 16 can be attached together with a pull tab cover 17 for fixing the pull tab 16 to the slider.
The components of the slide fastener are molded parts which can be produced by injection molding, and are known to be manufacturable from polyamides.
For example, DE 3 444 813 (Patent Document 1) discloses a method of injection molding a slider from a polyamide which has been reinforced with glass fibers for the purpose of improving durability of the slider used for a slide fastener for bedclothes against the washing and ironing, as well as a wear resistance of the slider to the sliding (claim 1). It discloses that a length of the glass fiber is 4 to 8 mm and its content is at least 25% by weight (claim 1). It discloses that the slider is subjected to a recrystallization treatment after being molded (claim 1). It also discloses that polyamide 6,6 is used as the polyamide (claim 6). Further, it also discloses that a slip additive- or gliding agent-free polyamide is used, and that the glass fiber content makes up about 40% by weight (claim 5).
Japanese Patent No. 4517277 (Patent Document 2) also discloses that polyamide resins can be used as parts for a slide fastener. This document mentions polyamide 6, polyamide 66, polyamide MXD6, polyamide 6T, polyamide 11, polyamide 12 and the like as the polyamide resins. It discloses that polyamide resins having 80 mol % or more of capramide repeating units and/or polyamide resins having 80 mol % or more of hexamethylene adipamide repeating units are particularly preferred.
WO 2013/098978 (Patent Document 3) discloses a polyamide resin composition containing 30 to 50% by mass of a polyamide and 50 to 70% by mass of reinforcing fibers, wherein 50% by mass or more in the polyamide is an aliphatic polyamide. Further, it discloses that in terms of improvement of a plating property, the aliphatic polyamide in the polyamide is preferably at least 80% by mass.